Posted by dellus on
URL: https://forum.librecad.org/Getting-dimensions-to-snap-accurately-on-drawing-almost-solved-tp5714481p5714482.html

Be sure to have "free snap" enabled too, so you can place the dimensioning line somewhere off the object.
You can also switch to "Ex"(exclusive snap mode) during the operation, after having set the reference points. This disables the other snap settings but still keeps them remembered. But be aware it automatically activates "snap to grid".